The objectives of the study are as follows: 1. Determine whether there is a correlation between ADPR polymer formation and the growth rate of a cell. 2. Determine whether NAD analogues in which substitutions have been made in the AMP moiety of the coenzyme are converted in vitro into ADPR polymer analogues. 3. If formation of ADPR polymer analogues are observed, it will be determined whether various antitumor purine analogues result in the formation of ADPR polymer analogues in vitro and in vivo. The results obtained in vivo will be correlated with therapeutic effectiveness. These studies will employ established tumor lines. Standard procedures employing radioisotopes, column and paper chromatography, and electrophoresis will be employed.